Laser printing with device that includes voice coil-activated lens

ABSTRACT

A laser scanning device for marking objects includes an optical port configured and arranged to receive a laser beam; a lens configured and arranged to focus the laser beam to modify a surface of a material to be marked; and an electrically controlled linear actuator coupled with the lens. The electrically controlled linear actuator is configured to move the lens linearly, thereby causing the laser beam to scan across the surface of the material to be marked as a result of changes in a refraction angle, of the laser beam passing through the lens, caused by the linear movement.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority from U.S. ProvisionalApplication No. 62/681,571 entitled “Laser Printing with Device ThatIncludes Voice Coil-Activated Lens” and filed on Jun. 6, 2018, which isincorporated herein by reference in its entirety.

BACKGROUND

Laser scanning devices are used for code marking applications onconsumer packages. The information printed includes expiration date,manufactured by, or one or two dimensional product barcodes. Suchdevices include a laser source that gives out a Gaussian beam of a fewmm in diameter with some slow divergence. The beam is then expanded andcollimated using a few lenses. The collimated beam is then scanned byusing scanning mirrors, e.g., a pair of galvanometers or a polygonscanner. The scanned collimated expanded beam is then collected by alens or lenses to focus the beam at some distance away on a target whereit burns a dot or mark. Such scanning of a beam across the surface ofthe focus lens usually has a distortion which is corrected by softwarethat instructs the scan mirrors how far (+/− degrees) it should scan tobring the focus on an undistorted grid line and thus avoid distortion. Alaser scanning device, also referred to as a scan head, containing theforegoing optics, scan mirrors and focus lenses, along with acontroller, electronic circuits and cooling fans, usually has a size inexcess of 6″×6″×7″. Some housings can be slightly smaller and yet someare larger.

SUMMARY

Implementations of a scan head described herein include a lens to focusa laser beam to modify a surface of a material to be marked, and avoice-coil actuator coupled with the lens. The voice-coil actuator movesthe lens linearly and, thus, causes the laser beam to scan across thesurface of the material to be marked as a result of changes in arefraction angle, of the laser beam passing through the lens, caused bythe linear movement. The disclosed scan head equally is usable with dotmatrix and vector type laser marking. As such, both dot matrix andvector style printing can be done using disclosed scanning methods. Thedisclosed scan head is compatible with different laser sources such asCO₂, UV and Long Infrared and can eliminate the need for usinggalvanometer and polygon scanners.

According to an aspect of the disclosed technologies, a laser scanningdevice for marking objects is described. The laser scanning deviceincludes an optical port configured and arranged to receive a laserbeam; a lens configured and arranged to focus the laser beam to modify asurface of a material to be marked; and an electrically controlledlinear actuator coupled with the lens. The electrically controlledlinear actuator is configured to move the lens linearly, thereby causingthe laser beam to scan across the surface of the material to be markedas a result of changes in a refraction angle, of the laser beam passingthrough the lens, caused by the linear movement.

The foregoing and other embodiments can each optionally include one ormore of the following features, alone or in combination. In someimplementations, the laser scanning device can include a first reflectoroptically coupled with the optical port, and a second reflectoroptically coupled with the first reflector and the lens. Here, the firstreflector is (i) arranged to receive the laser beam from the opticalport along a first direction, and (ii) configured to redirect the laserbeam to the second reflector along a second direction. Additionally, thesecond reflector is arranged to receive the laser beam along the seconddirection, and redirect the laser beam to the lens along a thirddirection.

In some of the foregoing implementations, the first reflector caninclude a first mirror, and the second reflector can include a secondmirror. In some of the foregoing implementations, the laser scanningdevice can include a translation stage that supports the first reflectorand the second reflector, in addition to the electrically controlledlinear actuator and thus the lens. Here, the translation stage isconfigured to move, as a unit, each of the first mirror, the secondmirror, the electrically controlled linear actuator, and the lens, alonga line that is parallel to the first direction. In some cases, thetranslation stage can include a table, a thread shaft, and a steppermotor.

In some of the foregoing implementations, the second direction is alongan X dimension in a three dimensional space, and the first reflector canbe arranged in a plane tilted at a fixed forty five degree anglerelative to a (X,Z)-plane and normal to a (X,Y)-plane in the threedimensional space. The third direction is along a Y dimension in thethree dimensional space, and the second mirror can be arranged in aplane tilted at a fixed forty five degree angle relative to the(X,Z)-plane and normal to a (Y,Z)-plane in the three dimensional space.Additionally, the first direction is along a Z dimension in the threedimensional space.

In some of the foregoing implementations, the electrically controlledlinear actuator can be a first electrically controlled linear actuatorconfigured to move the lens along the second direction. Here, the laserscanning device can include a second electrically controlled linearactuator coupled with the first electrically controlled linear actuator.The second electrically controlled linear actuator is configured to movethe first electrically controlled linear actuator, and thus the lens,along the third direction to adjust the focus of the laser beam on thesurface of the material to be marked.

In some of the foregoing implementations, the laser scanning device caninclude a third electrically controlled linear actuator coupled with thefirst electrically controlled linear actuator. The third electricallycontrolled linear actuator is configured to move, as a unit, the secondmirror and the first electrically controlled linear actuator, and thusthe lens, along the second direction to adjust a centered position ofthe lens, thereby providing an increased marking area for the laserscanning device.

In some implementations, the optical port can include a fiber opticcable connector configured to hold an output end of a fiber optic cable.The fiber optic cable connector can be disposed adjacent to the lens andarranged to direct to the lens along a third direction the laser beamguided through the fiber optic cable and output at its output end.

In some of the foregoing implementations, the laser scanning device caninclude a translation stage that supports the fiber optic cableconnector, and the electrically controlled linear actuator and thus thelens. The translation stage is configured to move, as a unit, each ofthe fiber optic cable connector, the electrically controlled linearactuator, and the lens, along a line that is parallel to a firstdirection orthogonal to the third direction. In some of the foregoingimplementations, the electrically controlled linear actuator can be afirst electrically controlled linear actuator configured to move thelens along a second dimension orthogonal to the first and thirddirections. Here, the laser scanning device can include a secondelectrically controlled linear actuator coupled with the firstelectrically controlled linear actuator. The second electricallycontrolled linear actuator is configured to move, as a unit, the fiberoptic cable connector, the first electrically controlled linearactuator, and thus the lens, farther along the second dimension toadjust a centered position of the lens, thereby providing an increasedmarking area for the laser scanning device.

In some of the foregoing implementations, the laser scanning device caninclude a third electrically controlled linear actuator coupled betweenthe first electrically controlled linear actuator and the secondelectrically controlled linear actuator. The third electricallycontrolled linear actuator is configured to move the first electricallycontrolled linear actuator, and thus the lens, along the third directionto adjust the focus of the laser beam on the surface of the material tobe marked.

In some of the foregoing implementations, a ratio of a diameter of thelens divided by a diameter of the laser beam can be between 1.1 and 5.1,between 1.1 and 4.1, between 1.1 and 3.1, or between 1.1 and 2.1. Here,the diameter of the laser beam can be about 2.5 mm, the diameter of thelens can be about 3.5 mm, and a scanning distance covered by the changesin the refraction angle between 15 mm and 57 mm.

In some of the foregoing implementations, any of the electricallycontrolled linear actuators referenced therein can include either avoice-coil actuator or a linear DC motor. In some of the foregoingimplementations, the linear motion of the lens caused by theelectrically controlled actuator coupled with the lens can be along alinear path or an arcuate path.

According to another aspect of the disclosed technologies, a lasermarking system includes a laser scan head including any one of some ofthe foregoing implementations of the laser scanning device.Additionally, the laser marking system includes a laser sourceconfigured and arranged to provide the laser beam to the optical port ofthe laser scan head along the first direction.

According to another aspect of the disclosed technologies, a lasermarking system includes a laser scan head including any one of some ofthe foregoing implementations of the laser scanning device.Additionally, the laser marking system includes a laser sourceconfigured and arranged to provide the laser beam, and the fiber opticcable connected at its input end to the laser source and at its outputend to the fiber optic cable connector of the laser scan head to guidethe laser beam from the laser source to the laser scan head.

The foregoing and other embodiments can each optionally include one ormore of the following features, alone or in combination. In someimplementations, the laser marking system can include a controllercoupled with the laser scan head and configured to send electricalsignals to the electrically controlled linear actuator to move the lensto effect dot matrix or vector type laser marking on products, when theproducts move in front of the laser scan head on a conveyor in a productmanufacturing or packaging facility.

According to another aspect of the disclosed technologies, a method ofoperating the laser marking system, substantially as shown anddescribed.

Particular aspects of the disclosed technologies can be implemented torealize one or more of the following potential advantages. For example,using a voice-coil actuator with spring return to activate a lens of ascan head is the most compact, lowest-cost and simplest to implementsolution for scan-head operation. For instance, the small size of thedisclosed scan heads enables their use for new printing applicationsthat cannot be performed with larger conventional scan heads which usegalvanometers for operation.

Details of one or more implementations of the disclosed technologies areset forth in the accompanying drawings and the description below. Otherfeatures, aspects, descriptions and potential advantages will becomeapparent from the description, the drawings and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D show aspects of a laser scanning technique which uses avoice-coil actuator to move a lens transversely to a laser beam forscanning the laser beam in the direction of the actuated motion.

FIGS. 1E-1H show aspects of a laser scanning technique which uses avoice-coil actuator to rotate a lens about a rotation axis orthogonal toa laser beam for scanning the laser beam in a direction orthogonal toboth the rotation axis and the laser beam.

FIGS. 2A-2C show aspects of a laser marking system which includes anexample of a scan head that uses a voice coil-actuated lens and discretebeam-steering optics.

FIGS. 3A-3B show aspects of a laser marking system which includesanother example of a scan head that uses a voice coil-actuated lens anda fiber optic cable.

FIGS. 4A-4B show an example of a scan head that uses discretebeam-steering optics to deliver a laser beam to a lens actuated by acombination of voice-coil actuators for scanning and focusing the laserbeam.

FIGS. 5A-5B show an example of a scan head that uses a fiber optic cableto deliver a laser beam to a lens actuated by a combination ofvoice-coil actuators for scanning and focusing the laser beam.

FIGS. 6A-6B show an example of a scan head that uses discretebeam-steering optics to deliver a laser beam to a lens actuated by acombination of voice-coil actuators for extending a range over which thelaser beam is being scanned.

FIGS. 7A-7B show an example of a scan head that uses a fiber optic cableto deliver a laser beam to a lens actuated by a combination ofvoice-coil actuators for extending a range over which the laser beam isbeing scanned.

FIG. 8 shows a laser marking system which includes an example of a scanhead that uses discrete beam-steering optics to deliver a laser beam toa lens actuated by a combination of voice-coil actuators for scanningthe laser beam along transverse directions orthogonal to each other.

FIG. 9 shows a laser marking system which includes an example of a scanhead that uses a fiber optic cable to deliver a laser beam to a lensactuated by a combination of voice-coil actuators for scanning the laserbeam along transverse directions orthogonal to each other.

FIG. 10 is a diagram of a laser marking system which includes a scanhead that uses one or more of the voice-coil actuators illustrated inthe previous figures to activate a lens for scanning a laser beam over aprinting target.

Certain illustrative aspects of the disclosed technologies are describedherein in connection with the following description and the accompanyingfigures. These aspects are, however, indicative of but a few of thevarious ways in which the principles of the disclosed technologies maybe employed and the disclosed technologies are intended to include allsuch aspects and their equivalents. Other advantages and novel featuresof the disclosed technologies may become apparent from the followingdetailed description when considered in conjunction with the figures.

DETAILED DESCRIPTION

FIGS. 1A-1D show aspects of a laser scanning technique which uses avoice-coil actuator 130 to move a lens 120 transversely to an incidentlaser beam 115 for scanning the laser beam in the direction of the lens'motion. FIGS. 1E-1H show aspects of a laser scanning technique whichuses a voice-coil actuator 130R to rotate the lens 120 about a rotationaxis 133 orthogonal to the incident laser beam 115 for scanning thelaser beam in a direction orthogonal to both the rotation axis and thelaser beam.

FIG. 1A is a cross-section view, e.g., parallel to the (y,z)-plane, of alaser-scanning device, also referred to as a scan head, 110, whichincludes the voice-coil actuator 130 and the lens 120 coupled with thevoice-coil actuator. FIG. 1E is a cross-section view, e.g., parallel tothe (y,z)-plane, of a scan head 110R, which includes the lens 120 andthe voice-coil actuator 130R coupled with the lens.

Referring to both FIGS. 1A and 1E, the voice-coil actuator 130, 130R,also referred to as a voice-coil motor, has a through hole, referred toas actuator aperture, 134, 134R. The actuator aperture, 134, 134R has anactuator-aperture axis 111. The lens 120 is coupled to the voice-coilactuator 130, 130R to cover the actuator aperture 134, 134R.

The scan head 110, 110R has a housing 112 and a scanning aperture 116,which is an opening in the housing. The voice-coil actuator 130, 130R isdisposed adjacent to the scanning aperture 116. The lens 120 coupled tothe voice-coil actuator 130, 130R (i) has an optical axis 121, e.g.,along the z-axis, and (ii) is facing outside the housing 112 through thescanning aperture 116. During operation of the scan head 110, 110R, anincident laser beam 115 provided to the scan head through an inputoptical port (not shown in FIGS. 1A-1H) is directed to the lens 120along the actuator-aperture axis 111 through the actuator aperture 134,134R. The lens 120 is configured to focus a transmitted laser beam 125to a target surface 195, which (i) is spaced apart from the lens by aworking distance W, e.g., along the z-axis, and (ii) extendstransversely to the actuator-aperture axis 111, e.g., parallel to the(x,y)-plane, within a field of view defined by the scanning aperture116. When the optical axis 121 of the lens 120 coincides with theactuator-aperture axis 111, the lens 120 focuses the transmitted laserbeam 125 at an intersection point 197 of the actuator-aperture axis withthe target surface 195. Note that the working distance W of the scanhead 110, 110R is determined by the focal length of the lens 120, whichhere is in the range of 15-50 mm.

Referring now to the example illustrated in FIG. 1A, the voice-coilactuator 130 is a voice-coil actuator with spring return, thus itincludes two or more springs 132 arranged to compress and extendorthogonal to the actuator-aperture axis 111, here along the y-axis. Assuch, when the voice-coil actuator 130 has been activated, the springs132 are configured to linearly move the lens 120 transversely to theactuator-aperture axis 111. The voice-coil actuator 130 works like asolenoid where a coil of wire is energized creating an electromagnet.The electromagnet is used to then draw in a metal shuttle that isattached to the lens 120 causing the lens to move. The springs 132within the voice-coil actuator 130 put a force on the lens 120 allowingthe lens to move back into its home position when power is removed fromthe electromagnet.

FIGS. 1B, 1C and 1D show instances of the scan head 110 at sequentialtimes t₁, t₂, t₃, respectively. At times t₁, t₂, t₃, the lens 120 hasbeen linearly moved along a linear path perpendicular to theactuator-aperture axis 111, such that instances of its optical axis121(t ₁), 121(t ₂), 121(t ₃) have shifted by corresponding lensdisplacements δy(t₁), δy(t₂), δy(t₃) relative to the actuator-apertureaxis. Note that a ratio of the lens 120's diameter and the actuatoraperture 134′ diameter is configured such that the lens covers theactuator aperture for any lens displacements |δy(t)|<δy_(MAX) caused bythe voice-coil actuator 130. However, because it is desirable for thevoice coil actuator 130 to move or tilt the lens 120 at high speeds,e.g., at speeds of order 32 ft./sec or higher which are comparable tolinear speeds of commercially available galvanometer scanning mirrors orpolygon scanners, the lens 120 should be very light. Therefore, the lens120 is configured to be just a little larger than a diameter of theincident laser beam 121. Since the diameter of the incident laser beam121 is about 3 mm or less, the lens 120's diameter is designed to be 5mm or less, for example in a range of 3.5-5 mm. As another example, aratio of a diameter of the lens 120 divided by a diameter of theincident laser beam 115 is between 1.1 and 5.1, between 1.1 and 4.1,between 1.1 and 3.1, or between 1.1 and 2.1.

Because at times t₁, t₂, t₃ the incident laser beam 115 impinges ondifferent portions of the lens 120, shifted relative to each other alongthe y-axis, instances of the transmitted laser beam 125(t ₁), 125(t ₂),125(t ₃) will be redirected by the lens, through refraction, relative tothe actuator-aperture axis 111 to different points of the target surface195 separated from the intersection point 197 by corresponding targetdisplacements ΔY(t₁), ΔY(t₂), ΔY(t₃). Note that, because the lens 120 isconfigured as a lens that is color corrected and free of sphericalaberrations, the target displacements ΔY(t₁), ΔY(t₂), ΔY(t₃) of pointson the target surface 195, where corresponding instances of thetransmitted laser beam 125(t ₁), 125(t ₂), 125(t ₃) will focus, aredeterministically related to (i) the lens displacements δy(t₁), δy(t₂),δy(t₃) of the instances of the optical axis 121(t ₁), 121(t ₂), 121(t ₃)of the lens 120, as imparted by the springs 132 of the voice-coilactuator 130, (ii) the refractive index of the material from which thelens 120 is made, and (iii) the wavelength of the laser beam 115incident on the lens. For instance, mappings of actuating voltages v(t)(to be applied to terminals of the voice-coil actuator 130) to lensdisplacements δy(t) to target displacements ΔY(t) will be establishedand stored, e.g., in look-up-tables. Such stored mappings {v(t), δy(t),ΔY(t)} can be provided to a controller (e.g., 1090 in FIG. 10) tocontrol operation of the scan head 110.

In other embodiments, not shown in FIGS. 1A-1D, the voice-coil actuator130 can be rotated by 90° about the z-axis, such that its springs 132are arranged to compress and extend along the x-axis. When thevoice-coil actuator has been activated, the springs 132 arranged in suchrotated configuration will linearly move the lens 120 transversely tothe actuator-aperture axis 111 and parallel to the x-axis, e.g.,in-and-out of the page. In such cases, target displacements ΔX(t) ofpoints on the target surface 195 where corresponding instances of thetransmitted laser beam will focus would be deterministically related, atleast, to lens displacements δx(t) of instances of the optical axis121(t) of the lens 120, as imparted by x-direction-moving springs of therotated voice-coil actuator 130.

Referring now to the example illustrated in FIG. 1E, the voice-coilactuator 130R is a voice-coil actuator with spring return, thus itincludes two or more springs 132R arranged to compress and extendparallel to the actuator-aperture axis 111, here along the z-axis. Assuch, when the voice-coil actuator 130R has been activated, the springs132R are configured to rotate the lens 120 about the rotation axis 133.Here, the optical axis 121 of the un-rotated lens 120 coincides with theactuator-aperture axis 111, and the rotation axis 133 is parallel to thex-axis. FIGS. 1F, 1G and 1H show instances of the scan head 110R atsequential times t₁, t₂, t₃, respectively. At times t₁, t₂, t₃, the lens120 has been rotated about the rotation axis 133, such that instances ofits optical axis 121(t ₁), 121(t ₂), 121(t ₃) have rotated bycorresponding lens rotations δθ(t₁), δθ(12), δθ(13) relative to theactuator-aperture axis 111. Note that a ratio of the lens 120's diameterand the actuator aperture 134R′ diameter is configured such that thelens covers the actuator aperture for any lens rotations|δθ(t)|<δθ_(MAX) caused by the voice-coil actuator 130R. Because attimes t₁, t₂, t₃ the incident laser beam 115 impinges on the lens 120 atdifferent orientations, rotated relative to each other about therotation axis 133, instances of the transmitted laser beam 125(t ₁),125(t ₂), 125(t ₃) will be redirected by the lens, through refraction,relative to the actuator-aperture axis 111 to different points of thetarget surface 195 separated from the intersection point 197 bycorresponding target displacements ΔY(t₁), ΔY(t₂), ΔY(t₃). Note that,because the lens 120 is configured as a lens that is color corrected andfree of spherical aberrations, the target displacements ΔY(t₁), ΔY(t₂),ΔY(t₃) of points on the target surface 195, where correspondinginstances of the transmitted laser beam 125(t ₁), 125(t ₂), 125(t ₃)will focus, are deterministically related to (i) the rotations δθ(t₁),δθ(12), δθ(13) about the rotation axis 133 (i.e., about the x-axis) ofthe instances of the optical axis 121(t ₁), 121(t ₂), 121(t ₃) of thelens 120, as imparted by the springs 132R of the voice-coil actuator130R, (ii) the refractive index of the material from which the lens 120is made, and (iii) the wavelength of the laser beam 115 incident on thelens. In this manner, mappings of actuating voltages v(t) (to be appliedto terminals of the voice-coil actuator 130R) to lens rotations 60(t) totarget displacements ΔY(t) will be established and stored, e.g., inlook-up-tables. Such stored mappings {θ(t), δy(t), ΔY(t)} can beprovided to a controller (e.g., 1090 in FIG. 10) to control operation ofthe scan head 110R.

In other embodiments, not shown in FIGS. 1E-1H, the voice-coil actuator130R can be rotated by 90° about the z-axis, such that its rotation axis133 are arranged parallel to the x-axis. When activated in such rotatedconfiguration, the springs 132R will rotate the lens 120 about therotation axis 133 now parallel to the x-axis, e.g., in-and-out of thepage. In such cases, rotations 60(t) about the y-axis of instances ofthe optical axis 121(t) of the lens 120, as imparted byz-direction-moving springs of the rotated voice-coil actuator 130R,would be deterministically related to target displacements ΔX(t) ofpoints on the target surface 195 where corresponding instances of thetransmitted laser beam will focus.

Referring now to FIGS. 1A-1H, the voice-coil actuator 130, 130R is asimple type of electric motor which includes magnetic housing and one ormore coils. When electricity passes through a coil, it produces amagnetic field that reacts with a permanent magnet to either repel orattract the coil. The movement of the coil is restricted such that itcan only move along its axis. Applying a voltage across terminals of thevoice-coil actuator 130, 130R causes the voice-coil actuator to move thelens 120 in one direction. Reversing the polarity of the applied voltagewill cause the voice-coil actuator 130, 130R to move the lens 120 to theopposite direction. The generated electromagnetic force is proportionalto the flux crossing the coil and the current that flows through thecoil. This force is almost constant in the specified stroke range of thevoice-coil actuator 130, 130R. Movements of the lens 120 caused by thevoice-coil actuator 130, 130R are repeatable and gearless, with the lens120′ position fixed by balancing electromagnetic and spring forces. Thesprings 132, 132R return the lens 120 to an un-compressed springposition, and no power is dissipated unless activation is required.Additionally, the voice-coil actuator 130, 130R is mechanically robust,shock-resistant, and has low-cost mechanics. Because the voice-coilactuator 130, 130R has no hysteresis, it has a directcurrent-vs-position relationship.

Also note that the laser beam 115 can be delivered to the lens 120 alongthe actuator-aperture axis 111 from the input optical port of each ofthe scan heads 110, 110R, either directly or over a beam path with anarbitrary number of two or more legs (aka path segments). Both types oflaser beam delivery are described below, starting with laser beamdelivery over a 3-legged beam path.

FIGS. 2A-2C show aspects of a laser marking system 200 which includes ascan head 210 that uses a voice coil-actuated lens 220/230 and discretebeam-steering optics 242, 244. FIG. 2A is a cross-section view, e.g.,parallel to the (x,y)-plane, of the laser marking system 200 whichincludes, in addition to the scan head 210, a laser source 202. FIGS.2B-2C are cross-section views, e.g., parallel to the (y,z)-plane, ofinstances of the scan head 210 corresponding to times t₁, t₂.

The scan head 210 has a housing 212. In addition to the beam steeringoptics 242, 244, the scan head 210 includes a lens 220 and a voice-coilactuator 230. The voice-coil actuator 230 has an actuator aperture 234,which has an actuator-aperture axis 211. The lens 220 is coupled to thevoice-coil actuator 230 to cover the actuator aperture 234. The lens220, the voice-coil actuator 230 and the beam steering optics 242, 244are encompassed by the housing 212. The housing 212 has an input opticalport 214, which is an opening in the housing. The laser source 202 caninclude one of a CO₂ laser, a UV laser or a Long Infrared laser. Thelaser source 202 is optically coupled to the scan head 210 to provide,during operation of the laser marking system 200, a laser beam 215 alonga first direction, e.g., parallel to the x-axis, the provided laser beamto be received inside the scan head through the input optical port 214.

The housing 212 also has a scanning aperture 216, which is anotheropening in the housing. Inside the housing 212, the scan head 210includes a chassis 217. The chassis 217 supports the voice-coil actuator230 adjacent to the scanning aperture 216. The lens 220 coupled to thevoice-coil actuator 230 (i) has an optical axis 221, e.g., along thez-axis, and (ii) is facing outside the housing 212 through the scanningaperture 216.

In the example illustrated in FIGS. 2A-2C, the beam steering opticsinclude a first reflector 242 supported by the chassis 217 in a planetilted at a fixed 45° angle relative to the (x,z)-plane and normal tothe (x,y)-plane. Additionally, the beam steering optics include a secondreflector 244 supported by the chassis 217 in a plane tilted at a fixed45° angle relative to the (x,z)-plane and normal to the (y,z)-plane. Thefirst reflector 242 is disposed on the chassis 217 to (i) receive fromthe input port 214 the laser beam 215 along the first direction, hereparallel to the x-axis, and (ii) redirect the laser beam to the secondreflector 244 along a second direction, here parallel to the y-axis. Thesecond reflector 244 is disposed on the chassis 217 to (i) receive fromthe first reflector 242 the laser beam 215 along the second direction,and (ii) redirect the laser beam to the lens 220 along a third directionwhich coincides with the actuator-aperture axis 211. Here, the firstreflector 242 and the second reflector 244 can be implemented asmirrors, reflecting prism surfaces, etc.

The lens 220 is configured to (i) receive from the second reflector 244the incident laser beam 215 along the actuator-aperture axis 211 throughthe actuator aperture 234, and (ii) focus the transmitted laser beam 225to a target surface 295. The target surface 295 (i) is spaced apart fromthe lens 220 by a working distance W along the actuator-aperture axis211, here along the z-axis, and (ii) extends transversely to theactuator-aperture axis, here parallel to the (x,y)-plane, within a fieldof view defined by the scanning aperture 216. In the example illustratedin FIGS. 2A-2C, a conveyor 291 suitably moves the target surface 295along the x-axis, such that the laser beam 225 transmitted through thelens 220 can be used to print, mark and/or burn a pattern (e.g., byablation or using phase changing inks) extending on the target surface295 along the x-axis.

The voice-coil actuator 230 includes two or more springs 232 arranged tocompress and extend orthogonal to the actuator-aperture axis 211, herealong the y-axis. As such, when the voice-coil actuator 230 has beenactivated, the springs 232 are configured to linearly move the lens 220transversely to the actuator-aperture axis 211. At times t₁, t₂ the lens220 has been linearly moved along a linear path perpendicular to theactuator-aperture axis 211, such that instances of its optical axis221(t ₁), 221(t ₂) have shifted by corresponding lens displacementsδy(t₁), δy(t₂) relative to the actuator-aperture axis. Note that at atime “t” when δy(t)=0, when the lens 220 is disposed such that itsoptical axis coincides with the actuator-aperture axis 211, the lensfocuses the transmitted laser beam 225 at an intersection point 297 ofthe actuator-aperture axis with the target surface 295. However, becauseat times t₁, t₂ the incident laser beam 215 impinges on differentportions of the lens 220, shifted relative to each other along they-axis, instances of the transmitted laser beam 225(t ₁), 225(t ₂) willbe redirected by the lens, through refraction, relative to theactuator-aperture axis 211 to different points of the target surface 295separated from the intersection point 297 by corresponding targetdisplacements ΔY(t₁), ΔY(t₂).

Note that this implementation of the voice-coil actuator 230 correspondsto the voice-coil actuator 130 described above in connection with FIGS.1A-1D. In another implementation, the voice-coil actuator 230 can beimplemented as the voice-coil actuator 130R described above inconnection with FIGS. 1E-1H.

Delivery of the laser beam 215 to the voice-coil actuated lens 220 overthe 3-legged beam path formed using the pair of reflectors 242, 244 isadvantageous because the pair of reflectors ensures a more effective andefficient alignment procedure of the third direction of the laser beam215 to the actuator-aperture axis 211. Note, however, that an overallsize of the scan head 210 can be 15 mm×15 mm×15 mm. The size of a scanhead along at least one direction, e.g., parallel to the y-axis, can bedecreased compared to the scan head 210 if the laser beam were delivereddirectly to the voice-coil actuated lens, over a shorter, direct beampath, as described below.

FIGS. 3A-3B are cross-section views, e.g., parallel to the (y,z)-plane,of instances of a laser marking system 300 corresponding to times t₁,t₂, where the laser marking system includes a scan head 310 that uses avoice coil-actuated lens 320/330 and a fiber optic cable 350. Here, thelaser marking system 300 includes a laser source 302, in addition to thescan head 310 and the fiber optic cable 350.

In some implementations, the laser source 302 can include a CO₂ laser.Here, the fiber optic cable 350 can include one or more optical fibersconfigured to guide light emitted by CO₂ lasers. E.g., PolycrystalineInfraRed (PIR) Fiber is commercially available (e.g., PIR 400, PIR630,PIR900). In other implementations, laser source 302 can include one of aUV laser or a Long Infrared laser. Here, the fiber optic cable 350 willinclude fiber optics made from materials configured to guide UV light,and Long Infrared light, respectively.

The scan head 310 has a housing 312. Also, the scan head 310 includes alens 320, a voice-coil actuator 330, and an input optical port 314.Here, the input optical port 314 is implemented as a fiber optic cableconnector. The voice-coil actuator 330 has an actuator aperture 334,which has an actuator-aperture axis 311. The lens 320 is coupled to thevoice-coil actuator 330 to cover the actuator aperture 334. The lens320, the voice-coil actuator 330 and the input optical port 314 areencompassed by the housing 312. The housing 312 has a scanning aperture316, which is an opening in the housing. Inside the housing 312, thescan head 310 also includes a chassis 317. The chassis 317 supports thevoice-coil actuator 330 adjacent to the scanning aperture 316. The lens320 coupled to the voice-coil actuator 330 (i) has an optical axis 321,e.g., along the z-axis, and (ii) is facing outside the housing 312through the scanning aperture 316. The chassis 317 also supports theinput optical port 314 adjacent to a side of the lens 320 opposing thelens side facing the scanning aperture 316.

The housing 312 also can have a source opening 318. The fiber opticcable 350 is connected at its input end to the laser source 302, crossesinside the housing 312 (e.g., through the source opening 318), and isconnected at its output end to the input optic port 314 adjacent to thelens 320. In this manner, the fiber optic cable 350 provides at itsoutput end, during operation of the laser marking system 300, laserlight from the laser source 302 in the form of a laser beam 315 directedto the lens 320 along the actuator-aperture axis 311. Note that thefiber optic cable 350 has been provided with a loop 352 of extra lengthto avoid stressing the fiber optic cable adjacent to the source opening318, and adjacent to the input optic port 314 (which is implemented as afiber optic cable connector). In some implementations, the loop 352 islocated outside of the housing 312 of the scan head 310 (e.g., the lasercrosses into the housing 312 through the optic port 314 being integratedwith the housing 312). Moreover, an overall size of the scan head 310can be 15 mm×7.5 mm×15 mm, which is smaller than the overall size of thescan head 210 at least along the y-axis.

The lens 320 is configured to (i) receive directly from the inputoptical port 314 the incident laser beam 315 along the actuator-apertureaxis 311 through the actuator aperture 334, and (ii) focus thetransmitted laser beam 325 to a target surface 395. The target surface395 (i) is spaced apart from the lens 320 by a working distance W alongthe actuator-aperture axis 311, here along the z-axis, and (ii) extendstransversely to the actuator-aperture axis, here parallel to the(x,y)-plane, within a field of view defined by the scanning aperture316. In the example illustrated in FIGS. 3A-3B, a conveyor 391 suitablymoves the target surface 395 along the x-axis, such that the laser beam325 transmitted through the lens 320 can be used to print, mark and/orburn a pattern (e.g., by ablation or using phase changing inks)extending on the target surface 395 along the x-axis.

The voice-coil actuator 330 includes two or more springs 332 arranged tocompress and extend orthogonal to the actuator-aperture axis 311, herealong the y-axis. As such, when the voice-coil actuator 330 has beenactivated, the springs 332 are configured to linearly move the lens 320transversely to the actuator-aperture axis 311. At times t₁, t₂corresponding to FIGS. 3A, 3B, respectively, the lens 320 has beenlinearly moved along a linear path perpendicular to theactuator-aperture axis 311, such that instances of its optical axis321(t ₁), 321(t ₂) have shifted by corresponding lens displacementsδy(t₁), δy(t₂) relative to the actuator-aperture axis. Note that at atime “t” when δy(t)=0, i.e., when the lens 320 is disposed such that itsoptical axis 321 coincides with the actuator-aperture axis 311, the lens320 focuses the transmitted laser beam 325 at an intersection point 397of the actuator-aperture axis with the target surface 395. However,because at times t₁, t₂ the incident laser beam 315 impinges ondifferent portions of the lens 320, shifted relative to each other alongthe y-axis, instances of the transmitted laser beam 325(t ₁), 325(t ₂)will be redirected by the lens, through refraction, relative to theactuator-aperture axis 311 to different points of the target surface 395separated from the intersection point 397 by corresponding targetdisplacements ΔY(t₁), ΔY(t₂).

In some cases, the working distance W can vary. For example, the targetsurface 295, 395 can belong to objects to be marked by the laser markingsystem 200, 300, which can be placed closer or farther away from thelens 220, 320. For such cases, to preserve print quality on targetobjects disposed at variable spacing to the lens 220, 320, the scan head210, 310 can be modified to allow for autofocusing the laser beam 225,325 transmitted through the lens 220, 320 onto the target objects. Themodification of the scan head 210 is described first, followed by themodification of the scan head 310.

FIGS. 4A-4B are cross-section views, e.g., parallel to the (y,z)-plane,of instances of a scan head 410 that uses discrete beam-steering optics442, 444 to deliver a laser beam 415 to a lens 420 actuated by acombination of voice-coil actuators 430, 460 for scanning and focusingthe laser beam 425 transmitted through the lens. The scan head 410 has ahousing 412. In addition to the beam steering optics 442, 444 and thelens 420, the scan head 410 includes a first voice-coil actuator 430 anda second voice-coil actuator 460. The lens 420 is coupled to the firstvoice-coil actuator 430, which is configured, e.g., like any one of thevoice-coil actuators 130, 230 or 330, to move the lens transverselyrelative to its optical axis 421. The first voice-coil actuator 430 iscoupled to the second voice-coil actuator 460. The second voice-coilactuator 460 is configured to move axially the first voice-coil actuator430, and thus the lens 420, i.e., along the lens' optical axis 421. Thesecond voice-coil actuator 460 includes two or more springs 462 arrangedto compress and extend along the lens 420's optical axis 421, here alongthe z-axis. As such, when the second voice-coil actuator 460 has beenactivated, the springs 462 are configured to displace the firstvoice-coil actuator 430, and thus the lens 420, by an axial displacementδz(t)≠0 relative to an axial datum 419 (here a particular surface of achassis 417). For instance, when the second voice-coil actuator 460 isnot activated, i.e., when δz(t)=0, the lens 420 is spaced apart from theaxial datum 419 by a predetermined axial distance Z₀. The firstvoice-coil actuator 430 and the second voice-coil actuator 460 combinedin this manner are said to form a voice-coil actuator assembly 465. Thevoice-coil actuator assembly 465 has an actuator-assembly aperture 467,which has an actuator-aperture axis 411. Note that, here, theactuator-assembly aperture 467 is formed from co-axial through holes ofthe first voice-coil actuator 430 and a second voice-coil actuator 460,respectively. The lens 420 is coupled to the first voice-coil actuator430 to cover the actuator-assembly aperture 467. The lens 420, thevoice-coil actuator assembly 465 and the beam steering optics 442, 444are encompassed by the housing 412.

The housing 412 has an input optical port (not shown in FIGS. 4A-4B)like the input optical port 212 described above in connection with FIG.2A. A laser source (not shown in FIGS. 4A-4B) provides, during operationof the scan head 410, through the input optical port a laser beam 415along a first direction, e.g., parallel to the x-axis. The housing 412also has a scanning aperture 416, which is another opening in thehousing. Inside the housing 412, the scan head 410 also includes thechassis 417 that supports the voice-coil actuator assembly 465 adjacentto the scanning aperture 416. Here, the second voice-coil actuator 460of the assembly 465 is coupled to the chassis 417, while the lens 420coupled to the first voice-coil actuator 430 of the assembly (i) isoriented with its optical axis 421 along the z-axis, and (ii) is facingoutside the housing 412 through the scanning aperture 416.

In the example illustrated in FIGS. 4A-4B, the beam steering optics 442,444 are (i) supported by the chassis 417 and (ii) implemented like thefirst and second reflectors 242, 244 described above in connection withFIGS. 2A-2C. In this manner, the first reflector 442 is disposed on thechassis 417 to (i) receive from the input port the laser beam 415 alongthe first direction and (ii) redirect the laser beam to the secondreflector 444 along a second direction, here parallel to the y-axis. Thesecond reflector 444 is disposed on the chassis 417 to (i) receive fromthe first reflector 442 the laser beam 415 along the second direction,and (ii) redirect the laser beam to the lens 420 along a thirddirection, which coincides with the actuator-aperture axis 411.

The lens 420 is configured to (i) receive from the second reflector 444the incident laser beam 415 along the actuator-aperture axis 411 throughthe actuator-assembly aperture 467, and (ii) focus the transmitted laserbeam 225 to a target surface 495, which is expected to be spaced apartfrom the lens by a working distance W along the actuator-aperture axis.The first voice-coil actuator 430, to which the lens is coupled,includes two or more springs 432 arranged to compress and extendorthogonal to the actuator-aperture axis 411, here along the y-axis. Assuch, when the first voice-coil actuator 430 has been activated, thesprings 432 are configured to linearly move the lens 420 transversely tothe actuator-aperture axis 411. At a time “t” the lens 420 has beenlinearly moved along a linear path perpendicular to theactuator-aperture axis 411, such that an instance of its optical axis421(t) has shifted by a corresponding lens displacement δy(t)≠0 relativeto the actuator-aperture axis. As described above in connection withFIGS. 2B-2C and 3A-3B, the finite lens displacement δy(t) causes that acorresponding instance of the transmitted laser beam 425(t) beredirected by the lens 420, through refraction, relative to theactuator-aperture axis 411 to a focal point in a focal plane spacedapart from the lens by the working distance W, the focal point separatedalong the y-axis from an axial focal point 497 by a corresponding targetdisplacement ΔY(t).

Note, however, that in FIG. 4A, which shows the instance of the scanhead 410 at time t₁, the optical axis 421 of the lens 420 is displacedby a lens displacement δy(t₁) relative to the actuator-aperture axis411, and the lens is spaced apart from the axial datum 419 by Z₀. Underthese conditions, the transmitted beam 425(t ₁) is out-of-focus when itimpinges on the target surface 495, because the target surface isfarther away from the focal plane by W(t₁)−W. This causes thetransmitted beam 425(t ₁) to impinge on the target surface 495 as a“blurred” spot (instead of as a “sharp” in-focus point) separated alongthe y-axis from the actuator-aperture axis 411 by a target displacementΔY_(B) larger than the expected ΔY(t₁). FIG. 4B shows that, at t₂, for alens displacement of the optical axis 421(t ₂) of the lens 420 equal tothe one at t₁, δy(t₂)=δy(t₁), the second voice-coil actuator 460 hasbeen activated using an autofocus procedure to move the first voice-coilactuator 430, and thus the lens, by an axial displacementδz(t₂)=W(t₁)−W. This projects the focal plane of the lens 420 onto thetarget surface 495. As such, at t₂ when δy(t₂)=δy(t₁), the transmittedbeam 425(t ₂) impinges on the target surface 495 as a sharp, in-focuspoint separated along the y-axis from the actuator-aperture axis 411 bya target displacement ΔY(t₂)=ΔY(t₁). The second voice-coil actuator 460can produce axial shifts, here along the actuator-aperture axis 411, ina range of 5-15 mm, e.g., ±5 mm from the focus distance setup during theinstallation.

The noted autofocus procedure used for actuating the second voice-coilactuator 460 can be performed in real-time using known opticaltriangulation methods for determining the position of the target surface495 relative the lens 420. A triangulation system can be used thatincludes a laser diode, one or more collection lenses, and a sensorhaving an array of pixels. For instance, the laser diode beam can directa laser diode beam through a collection lens to the target surface 495at an oblique angle. The same or another collection lens can collect areturn beam scattered by the target surface and can direct the returnbeam on the array of pixels. Calibration aspects of this triangulationmethod include information relating (i) the pixel position of the centerof the return beam on the array of pixels and to (ii) the distancebetween the lens 420 and the target surface 495. As such, when thedistance along the z-axis between the lens 420 and the target surface495 changes, the return beam will be scattered at a different angle, sothe collection lens will direct it to a different position on the arrayof pixels. Once the triangulation system determines the magnitude anddirection in which the lens 420 is displaced relative to the targetsurface 495 along the z-axis, the second voice-coil actuator 460 will beactivated to move the lens 420 along the z-axis in real-time, as needed.

An autofocus modification similar to the one described above can beimplemented for the scan head 310. FIGS. 5A-5B are cross-section views,e.g., parallel to the (y,z)-plane, of instances of a scan head 510 thatuses a fiber optic cable 550 to deliver a laser beam 515 to a lens 520actuated by a combination of voice-coil actuators 530, 560 for scanningand focusing the laser beam 525 transmitted through the lens. The scanhead 510 has a housing 512. In addition to the lens 520, the scan head510 includes a first voice-coil actuator 530 and a second voice-coilactuator 560. The lens 520 is coupled to the first voice-coil actuator530, which is configured, e.g., like any one of the voice-coil actuators130, 130R, 230, 330 or 430, to move the lens transversely relative toits optical axis 521. The first voice-coil actuator 530 is coupled tothe second voice-coil actuator 560. The second voice-coil actuator 560is configured to move axially the first voice-coil actuator 530, andthus the lens 520, i.e., along the lens' optical axis 521. The secondvoice-coil actuator 560 includes two or more springs 562 arranged tocompress and extend along the lens 520's optical axis 521, here alongthe z-axis. As such, when the second voice-coil actuator 560 has beenactivated, the springs 562 are configured to displace the firstvoice-coil actuator 530, and thus the lens 520, by an axial displacementδz(t)≠0 relative to an axial-datum 519 (here a particular surface of achassis 517). For instance, when the second voice-coil actuator 560 isnot activated, i.e., when δz(t)=0, the lens 520 is spaced apart from theaxial datum 519 by a predetermined axial distance Z₀. The firstvoice-coil actuator 530 and the second voice-coil actuator 560 combinedin this manner are said to form a voice-coil actuator assembly 565. Thevoice-coil actuator assembly 565 has an actuator-assembly aperture 567,which has an actuator-aperture axis 511. Note that, here, theactuator-assembly aperture 567 is formed from co-axial through holes ofthe first voice-coil actuator 530 and the second voice-coil actuator560, respectively. The lens 520 is coupled to the first voice-coilactuator 530 to cover the actuator-assembly aperture 567. The scan head510 further includes an input optical port 514, e.g., implemented as theinput port 314 described above in connection with FIGS. 3A-3B. The lens520, the voice-coil actuator assembly 565 and the input optical port 514are encompassed by the housing 512.

The housing 512 has a scanning aperture 516, which is an opening in thehousing. Inside the housing 512, the scan head 510 also includes thechassis 517 that supports the voice-coil actuator assembly 565 adjacentto the scanning aperture 516. Here, the second voice-coil actuator 560of the assembly 565 is coupled to the chassis 517, while the lens 520coupled to the first voice-coil actuator 530 of the assembly (i) isoriented with its optical axis 521 along the z-axis, and (ii) is facingoutside the housing 512 through the scanning aperture 516. The chassis517 also supports the input optical port 514 adjacent to a side of thelens 520 opposing the lens side facing the scanning aperture 516. Thehousing 512 can have a source opening (not shown in FIGS. 5A-5B) likethe source opening 318 described above in connection with FIGS. 3A-3B.The fiber optic cable 550 is connected at its input end to a lasersource, crosses inside the housing 512 (e.g., through the sourceopening), and is connected at its output end to the input optic port 514adjacent to the lens 520. In this manner, the fiber optic cable 550provides at its output end, during operation of the scan head 510, laserlight from the laser source in the form of a laser beam 515 directed tothe lens 520 along the actuator-aperture axis 511.

The lens 520 is configured to (i) receive directly from the inputoptical port 514 the incident laser beam 515 along the actuator-apertureaxis 511 through the actuator-assembly aperture 567, and (ii) focus thetransmitted laser beam 525 to a target surface 595, which is expected tobe spaced apart from the lens by a working distance W along theactuator-aperture axis. The first voice-coil actuator 530, to which thelens is coupled, includes two or more springs 532 arranged to compressand extend orthogonal to the actuator-aperture axis 511, here along they-axis. As such, when the first voice-coil actuator 530 has beenactivated, the springs 532 are configured to linearly move the lens 520transversely to the actuator-aperture axis 511. At a time “t”, the lens520 has been linearly moved along a linear path perpendicular to theactuator-aperture axis 511, such that an instance of its optical axis521(t) has shifted by a corresponding lens displacement δy(t)≠0 relativeto the actuator-aperture axis. As described above in connection withFIGS. 2B-2C and 3A-3B, the finite lens displacement δy(t) causes that acorresponding instance of the transmitted laser beam 525(t) beredirected by the lens 520, through refraction, relative to theactuator-aperture axis 511 to a focal point in a focal plane spacedapart from the lens by the working distance W, the focal point separatedalong the y-axis from an axial focal point 597 by a corresponding targetdisplacement ΔY(t).

Note, however, that in FIG. 5A, which shows the instance of the scanhead 510 at time t₁, the optical axis 521(t ₁) of the lens 520 isdisplaced by a lens displacement δy(t₁), and the lens is spaced apartfrom the axial datum 519 by Z₀. Under these conditions, the transmittedbeam 525(t ₁) is out-of-focus when it impinges on the target surface595, because the target surface is farther away from the focal plane byW(t₁)−W. This causes the transmitted beam 525(t ₁) to impinge on thetarget surface 595 as a “blurred” spot (instead of as a “sharp” in-focuspoint) separated along the y-axis from the actuator-aperture axis 511 bya target displacement ΔY_(B) larger than the expected ΔY(t₁). FIG. 5Bshows that, at t₂, for a lens displacement of the optical axis 521(t ₂)of the lens 520 equal to the one at t₁, δy(t₂)=δy(t₁), the secondvoice-coil actuator 560 has been activated using an autofocus procedureto move the first voice-coil actuator 530, and thus the lens, by anaxial displacement δz(t₂)=W(t₁)−W. This projects the focal plane of thelens 520 onto the target surface 595. As such, at t₂ when δy(t₂)=δy(t₁),the transmitted beam 525(t ₂) impinges on the target surface 595 as asharp, in-focus point separated along the y-axis from theactuator-aperture axis 511 by a target displacement ΔY(t₂)=ΔY(t₁). Thenoted autofocus procedure used for actuating the second voice-coilactuator 560 can be performed in real-time using known opticaltriangulation methods for determining the position of the target surface595 relative the lens 520, as described above in connection with thescan head 410.

Referring again to FIGS. 2A-2C and 3A-3B, the voice-coil actuator 230,330 of the scan head 210, 310 can sweep the transmitted laser beam 225,335 along the y-axis over a maximum scanning range 2ΔY_(MAX). For theabove-noted working distance W, the maximum scanning range can bebetween 15-57 mm.

In some cases, a pattern to be printed onto/burned into a targetsurface, e.g., 295, 395, 495, 595, extends over a range that is largerthan a scanning extent, e.g., 2ΔY_(MAX), achievable by actuating thevoice-coil actuator 230, 330, 430, 530 to which the lens 220, 320, 420,520 is coupled. For such cases, the scan head 210, 310, 410, 510 can bemodified to shift the actuator-aperture axis 211, 311, 411, 511 alongthe scanning direction by a desired distance δY_(C) to increase thescanning extent e.g., to 2ΔY_(MAX)+δY_(C). The modification of the scanhead 210, 410 is described first, followed by the modification of thescan head 310, 510.

FIGS. 6A-6B are cross-section views, e.g., parallel to the (y,z)-plane,of instances of a scan head 610 that uses discrete beam-steering optics642, 644 to deliver a laser beam 615 to a lens 620 actuated by acombination of voice-coil actuators 630, 670 for extending a range overwhich the laser beam 625 transmitted through the lens is being scanned.The scan head 610 has a housing 612. In addition to the beam steeringoptics 642, 644 and the lens 620, the scan head 610 includes a firstvoice-coil actuator 630 and a second voice-coil actuator 670. The lens620, the first voice-coil actuator 630, the second voice-coil actuator670, and the beam steering optics 642, 644 are encompassed by thehousing 612.

The first voice-coil actuator 630 has a first actuator aperture 634,which has a first actuator-aperture axis 611, here along the z-axis. Thelens 620 is coupled to the first voice-coil actuator 630 to cover thefirst actuator aperture 634. The first voice-coil actuator 630 isconfigured, e.g., like any one of the voice-coil actuators 130, 230,330, 430 or 530, to move the lens 620 transversely relative to the firstactuator-aperture axis 611, here along the y-axis. The first voice-coilactuator 630 is coupled to the second voice-coil actuator 670 through acoupling frame 617C. A chassis 617 of the scan head 610 supports thesecond voice-coil actuator 670 at a fixed location of the housing 612.The coupling frame 617C is configured to orient the first voice-coilactuator 630 and the second voice-coil actuator 670 relative to eachother such that, when activated, the second voice-coil actuator 670moves the first voice-coil actuator, and thus the firstactuator-aperture axis 611, along a direction of the lens 620's motioncaused by the first voice-coil actuator, here along the y-axis. Thesecond voice-coil actuator 670 includes two or more springs 672 arrangedto compress and extend along the y-axis. As such, when the secondvoice-coil actuator 670 has been activated, the springs 672 areconfigured to cause the second voice-coil actuator 670 to displace thefirst voice-coil actuator 630, and thus the first actuator-aperture axis611 and the lens 620, by an additional displacement δY_(C)≠0 relative toa transverse datum 619 (here a particular surface of the chassis 617).For instance, when the second voice-coil actuator 670 is not activated,e.g., when δY_(C)=0, the first actuator-aperture axis 611 is spacedapart from the transverse datum 619 by a predetermined transversedistance Y₀. The first voice-coil actuator 630 and the second voice-coilactuator 670 combined in this manner are said to form a voice-coilactuator assembly 675.

The housing 612 has an input optical port (not shown in FIGS. 6A-6B)like the input optical port 214 described above in connection with FIG.2A. A laser source (not shown in FIGS. 6A-6B) provides, during operationof the scan head 610, through the input optical port a laser beam 615along a first direction, e.g., parallel to the x-axis. The housing 612also has a scanning aperture 616, which is another opening in thehousing. The chassis 617 supports the voice-coil actuator assembly 675adjacent to the scanning aperture 616. In this manner, the lens 620coupled to the first voice-coil actuator 630 of the assembly (i) isoriented with its optical axis 621 along the z-axis, and (ii) is facingoutside the housing 612 through the scanning aperture 616.

In the example illustrated in FIGS. 6A-6B, the beam steering optics 642,644 are (i) supported by the chassis 617 and the coupling frame 617C,respectively, and (ii) implemented like the first and second reflectors242, 244 described above in connection with FIGS. 2A-2C. Also in theexample illustrated in FIGS. 6A-6B, the second voice-coil actuator 670has a second actuator aperture 674, which has a second actuator-apertureaxis 671, here along the y-axis. In this manner, the first reflector 642is disposed on the chassis 617 to (i) receive from the input port thelaser beam 615 along the first direction and (ii) redirect the laserbeam to the second reflector 644 along a second direction, whichcoincides with the second actuator-aperture axis 671. The secondreflector 644 is disposed on the coupling frame 617C to (i) receive fromthe first reflector 642 the laser beam 615 along the secondactuator-aperture axis 671, and (ii) redirect the laser beam to the lens620 along a third direction, which coincides with the firstactuator-aperture axis 611.

The lens 620 is configured to (i) receive from the second reflector 644the incident laser beam 615 along the first actuator-aperture axis 611through the first actuator aperture 634, and (ii) focus the transmittedlaser beam 625 to a target surface 695. The target surface 695 (i) isspaced apart from the lens 620 by a working distance W along the firstactuator-aperture axis 611, here along the z-axis, and (ii) extendstransversely to the first actuator-aperture axis, here parallel to the(x,y)-plane, within a field of view defined by the scanning aperture616. The first voice-coil actuator 630 includes two or more springs 632arranged to compress and extend orthogonal to the firstactuator-aperture axis 611, here along the y-axis. As such, when thefirst voice-coil actuator 630 has been activated, the springs 632 areconfigured to linearly move the lens 620 transversely to the firstactuator-aperture axis 611. At a time “t”, the lens 620 has beenlinearly moved along a linear path perpendicular to the firstactuator-aperture axis 611, such that an instance of its optical axis621(t) has shifted by a corresponding lens displacement δy(t)≠0 relativeto the first actuator-aperture axis. As described above in connectionwith FIGS. 2B-2C, 3A-3B, 4A-4B and 5A-5B, the finite lens displacementδy(t) causes that a corresponding instance of the transmitted laser beam625(t) be redirected by the lens 620, through refraction, relative tothe first actuator-aperture axis 611 to a point of the target surface695 separated along the y-axis from an axial focal point 697(t) by acorresponding target displacement ΔY(t).

Note, however, that in FIG. 6A, which shows the instance of the scanhead 610 at time t₁, the optical axis 621 of the lens 620 is displacedby a lens displacement δy(t₁) relative to the instant firstactuator-aperture axis 611(t ₁), and the first actuator-aperture axis isspaced apart from the transverse datum 619 by y_(C)(t₁)=Y₀. Under theseconditions, the transmitted beam 625(t ₁) impinges on the target surface695 at a point that (i) is separated by the instant axial focal point697(t ₁) by a target displacement ΔY(t₁), but (ii) misses apredetermined point 699 by a distance δY_(C). FIG. 6B shows that, at t₂,for a lens displacement of the optical axis 621 of the lens 620 relativeto the instant first actuator-aperture axis 611(t ₂) equal to the one att₁, δy(t₂)=δy(t₁), the second voice-coil actuator 670 has been activatedusing a scanning-range extension procedure to move the first voice-coilactuator 630, and thus the first actuator-aperture axis and the lens, byan additional displacement δY_(C). This shifts the firstactuator-aperture axis 611 by δY_(C). As such, at t₂ when δy(t₂)=δy(t₁),the transmitted beam 625(t ₂) impinges on the target surface 695 at thepredetermined point 699 separated along the y-axis from theδY_(C)-shifted axial focal point 697(t ₂) by a target displacementΔY(t₂)=ΔY(t₁).

A scanning-range extension similar to the one described above can beimplemented for a scan head that also has an additional voice-coilactuator used for autofocus, such as the scan head 410. Likewise, ascanning-range extension similar to the one described above can beimplemented for the scan head 310. FIGS. 7A-7B are cross-section views,e.g., parallel to the (y,z)-plane, of instances of a scan head 710 thatuses a fiber optic cable 750 to deliver a laser beam 715 to a lens 720actuated by a combination of voice-coil actuators 730, 770 for extendinga range over which the laser beam 725 transmitted through the lens isbeing scanned. The scan head 710 has a housing 712. In addition to thelens 720, the scan head 710 includes a first voice-coil actuator 730 anda second voice-coil actuator 770. The scan head 710 further includes aninput optical port 714, e.g., implemented as the input port 314described above in connection with FIGS. 3A-3B. The lens 720, the firstvoice-coil actuator 730, the second voice-coil actuator 770, and theinput optical port 714 are encompassed by the housing 712.

The first voice-coil actuator 730 has a first actuator aperture 734,which has a first actuator-aperture axis 711, here along the z-axis. Thelens 720 is coupled to the first voice-coil actuator 730 to cover thefirst actuator aperture 734. The first voice-coil actuator 730 isconfigured, e.g., like any one of the voice-coil actuators 130, 230,330, 430, 530 or 630, to move the lens 720 transversely relative to thefirst actuator-aperture axis 711, here along the y-axis. The firstvoice-coil actuator 730 is coupled to the second voice-coil actuator 770through a coupling frame 717C. A chassis 717 of the scan head 710supports the second voice-coil actuator 770 at a fixed location of thehousing 712. The coupling frame 717C is configured to orient the firstvoice-coil actuator 730 and the second voice-coil actuator 770 relativeto each other such that, when activated, the second voice-coil actuator770 moves the first voice-coil actuator, and thus the firstactuator-aperture axis 711, along a direction of the lens 720's motioncaused by the first voice-coil actuator, here along the y-axis. Thesecond voice-coil actuator 770 includes two or more springs 772 arrangedto compress and extend along the y-axis. As such, when the secondvoice-coil actuator 770 has been activated, the springs 772 areconfigured to cause the second voice-coil actuator 770 to displace thefirst voice-coil actuator 730, and thus the first actuator-aperture axis711 and the lens 720, by an additional displacement δY_(C)≠0 relative toa transverse datum 719 (here a particular surface of the chassis 717).For instance, when the second voice-coil actuator 770 is not activated,e.g., when δY_(C)=0, the first actuator-aperture axis 711 is spacedapart from the transverse datum 719 by a predetermined transversedistance Y₀. The first voice-coil actuator 730 and the second voice-coilactuator 770 combined in this manner are said to form a voice-coilactuator assembly 775.

The housing 712 has a scanning aperture 716, which is an opening in thehousing. The chassis 717 supports the voice-coil actuator assembly 775adjacent to the scanning aperture 716. In this manner, the lens 720coupled to the first voice-coil actuator 730 of the assembly (i) isoriented with its optical axis 721 along the z-axis, and (ii) is facingoutside the housing 712 through the scanning aperture 716. The couplingframe 717C supports the input optical port 714 adjacent to a side of thelens 720 opposing the lens side facing the scanning aperture 716. Thehousing 712 can have a source opening (not shown in FIGS. 7A-7B) likethe source opening 318 described above in connection with FIGS. 3A-3B.The fiber optic cable 750 is connected at its input end to a lasersource, crosses inside the housing 712 (e.g., through the sourceopening), and is connected at its output end to the input optic port 714adjacent to the lens 720. In this manner, the fiber optic cable 750provides at its output end, during operation of the scan head 710, laserlight from the laser source in the form of a laser beam 715 directed tothe lens 720 along the first actuator-aperture axis 711.

The lens 720 is configured to (i) receive directly from the inputoptical port 714 the incident laser beam 715 along the firstactuator-aperture axis 711 through the first actuator aperture 734, and(ii) focus the transmitted laser beam 725 to a target surface 795. Thetarget surface 795 (i) is spaced apart from the lens 720 by a workingdistance W along the first actuator-aperture axis 711, here along thez-axis, and (ii) extends transversely to the first actuator-apertureaxis, here parallel to the (x,y)-plane, within a field of view definedby the scanning aperture 716. The first voice-coil actuator 730 includestwo or more springs 732 arranged to compress and extend orthogonal tothe first actuator-aperture axis 711, here along the y-axis. As such,when the first voice-coil actuator 730 has been activated, the springs732 are configured to linearly move the lens 720 transversely to thefirst actuator-aperture axis 711. At a time “t”, the lens 720 has beenlinearly moved along a linear path perpendicular to the firstactuator-aperture axis 711, such that an instance of its optical axis721(t) has shifted by a corresponding lens displacement δy(t)≠0 relativeto the first actuator-aperture axis. As described above in connectionwith FIGS. 2B-2C, 3A-3B, 4A-4B, 5A-5B and 6A-6B, the finite lensdisplacement δy(t) causes that a corresponding instance of thetransmitted laser beam 725(t) be redirected by the lens 720, throughrefraction, relative to the first actuator-aperture axis 711 to a pointof the target surface 795 separated along the y-axis from an axial focalpoint 797(t) by a corresponding target displacement ΔY(t).

Note, however, that in FIG. 7A, which shows the instance of the scanhead 710 at time t₁, the optical axis 721 of the lens 720 is displacedby a lens displacement δy(t₁) relative to the instant firstactuator-aperture axis 711(t ₁), and the first actuator-aperture axis isspaced apart from the transverse datum 619 by y_(C)(t₁)=Y₀. Under theseconditions, the transmitted beam 725(t ₁) impinges on the target surface795 at a point that (i) is separated by the instant axial focal point797(t ₁) by a target displacement ΔY(t₁), but (ii) misses apredetermined point 799 by a distance δY_(C). FIG. 7B shows that, at t₂,for a lens displacement of the optical axis 721 of the lens 720 relativeto the instant first actuator-aperture axis 711(t ₂) equal to the one att₁, δy(t₂)=δy(t₁), the second voice-coil actuator 770 has been activatedusing a scanning-range extension procedure to move the first voice-coilactuator 730, and thus the first actuator-aperture axis and the lens, byan additional displacement δY_(C). This shifts the firstactuator-aperture axis 711 by δY_(C). As such, at t₂ when δy(t₂)=δy(t₁),the transmitted beam 725(t ₂) impinges on the target surface 795 at thepredetermined point 799 separated along the y-axis from theδY_(C)-shifted axial focal point 697(t ₂) by a target displacementΔY(t₂)=ΔY(t₁).

A scanning-range extension similar to the one described above can beimplemented for a scan head that also has an additional voice-coilactuator used for autofocus, such as the scan head 510. Referring now toFIGS. 6A-6B and 7A-7B, the second voice-coil actuator 670, 770 of thescan head 610, 710 can shift the first actuator-aperture axis 611, 711along the y-axis over a maximum y-displacement δY_(CMAX). In someimplementations of the second voice-coil actuator 670, 770, the maximumy-displacement can be between 100-200 mm.

In some cases, to print/burn a pattern having a particular transversesize on a target surface 295, 395, e.g., disposed parallel to the(x,y)-plane, the target surface will not be translated relative to thescan head 210, 310 along the transverse direction 291, 391, e.g., alongthe x axis, while the scan head scans the transmitted laser beam 225,335 along a scanning direction, e.g., along the y-axis, normal to thetransverse direction. Instead, the target surface 295, 395 will be keptat rest relative to the scan head 210, 310. For such cases, the scanhead 210, 310 can be modified to shift the actuator-aperture axis 211,311 parallel to the transverse direction, here along the x-axis, over adistance δX_(C) that exceeds the particular transverse size of theparticular pattern. The modification of the scan head 210, 410, 610 isdescribed first, followed by the modification of the scan head 310, 510,710.

FIG. 8 is a cross-section view, e.g., parallel to the (x,y)-plane, of alaser marking system 800 which includes a scan head 810 that usesdiscrete beam-steering optics 842, 844 to deliver a laser beam 815 to alens 820 actuated by a combination of a voice-coil actuator 830 and atranslation stage 880 for scanning the laser beam transmitted throughthe lens along transverse directions orthogonal to each other. The scanhead 810 has a housing 812. In addition to the beam steering optics 842,844 and the lens 820, the scan head 810 includes a voice-coil actuator830 and a translation stage 880. The lens 820, the voice-coil actuator830, the translation stage 880, and the beam steering optics 842, 844are encompassed by the housing 812.

The voice-coil actuator 830 has an actuator aperture 834, which has anactuator-aperture axis 811, here along the z-axis (into the page). Thelens 820 is coupled to the voice-coil actuator 830 to cover the actuatoraperture 834. The voice-coil actuator 830 is configured, e.g., like anyone of the voice-coil actuators 130, 230, 330, 430, 530, 630 or 730, tomove the lens 820 transversely relative to the actuator-aperture axis811, here along the y-axis. Here, the translation stage 880 includes arail 882 and a shuttle 884, also referred to as slide table. The rail882 is supported, at a fixed location of the housing 812, directly on,or itself is a portion of, a chassis of the housing. For example, therail 882 can be implemented as a thread shaft and stepper motor. Asanother example, the rail 882 can be a groove of the chassis. In eithercase, actuators used to move the shuttle 884 can be a solenoid or a DCServo. The voice-coil actuator 830 is coupled to the shuttle 884 througha coupling frame 817C. The coupling frame 817C is configured to orientthe voice-coil actuator 830 and the translation stage 880 relative toeach other such that, when activated, the shuttle 884 moves thevoice-coil actuator, and thus the actuator-aperture axis 811, orthogonalto a direction of the lens 820's motion caused by the voice-coilactuator, here along the y-axis. As such, when activated, the shuttle884 is configured to displace the voice-coil actuator 830, and thus theactuator-aperture axis 811 and the lens 820, by a transversedisplacement δX_(C)≠0 relative to a transverse datum 889 (here aparticular surface of the rail 882).

The housing 812 has an input optical port 814 implemented like the inputoptical port 214 described above in connection with FIG. 2A. A lasersource 802 provides, during operation of the laser marking system 800,through the input optical port 814 of the scan head 810 a laser beam 815along a first direction, e.g., parallel to the x-axis. The housing 812also has a scanning aperture 816, which is another opening in thehousing. The translation stage 880 supports the voice-coil actuator 830adjacent to the scanning aperture 816. In this manner, the lens 820coupled to the voice-coil actuator 830 (i) is oriented with its opticalaxis along the z-axis (here into the page), and (ii) is facing outsidethe housing 812 through the scanning aperture 816.

In the example illustrated in FIG. 8, the beam steering optics 842, 844are (i) supported by the shuttle 884 and the coupling frame 817C,respectively, and (ii) implemented like the first and second reflectors242, 244 described above in connection with FIGS. 2A-2C. In this manner,the first reflector 842 is disposed on the shuttle 884 to (i) receivefrom the input port the laser beam 815 along the first direction and(ii) redirect the laser beam to the second reflector 844 along a seconddirection, here along the y-axis. The second reflector 844 is disposedon the coupling frame 817C to (i) receive from the first reflector 842the laser beam 815 along the y-axis, and (ii) redirect the laser beam tothe lens 820 along a third direction (into the page), which coincideswith the actuator-aperture axis 811. The lens 820 is configured to (i)receive from the second reflector 844 the incident laser beam 815 alongthe actuator-aperture axis 811 through the actuator aperture 834, and(ii) focus the transmitted laser beam (not visible in FIG. 8) to atarget surface 895.

FIG. 9 is a cross-section view, e.g., parallel to the (x,y)-plane, of alaser marking system 900 which includes a scan head 910 that uses afiber optic cable 950 to deliver a laser beam to a lens 920 actuated bya combination a voice-coil actuator 930 and a translation stage 980 forscanning the laser beam transmitted through the lens along transversedirections orthogonal to each other. The scan head 910 has a housing912. In addition to the lens 920, the scan head 910 includes thevoice-coil actuator 930 and the translation stage 980. The scan head 910further includes an input optical port 914, e.g., implemented as theinput port 314 described above in connection with FIGS. 3A-3B. The lens920, the voice-coil actuator 930, the translation stage 980, and theinput optical port 914 are encompassed by the housing 912.

The voice-coil actuator 930 has an actuator aperture 934, which has anactuator-aperture axis 911, here along the z-axis (into the page). Thelens 920 is coupled to the voice-coil actuator 930 to cover the actuatoraperture 934. The voice-coil actuator 930 is configured, e.g., like anyone of the voice-coil actuators 130, 230, 330, 430, 530, 630 or 730, tomove the lens 920 transversely relative to the actuator-aperture axis911, here along the y-axis. Here, the translation stage 980 includes arail 982 and a shuttle 984. The rail 982 is supported, at a fixedlocation of the housing 912, directly on, or itself is a portion of, achassis of the housing. The translation stage 980 can be implementedsimilarly to the translation stage 880 described above in connectionwith FIG. 8.

The voice-coil actuator 930 is coupled to the shuttle 984 through acoupling frame 917C. The coupling frame 917C is configured to orient thevoice-coil actuator 930 and the translation stage 980 relative to eachother such that, when activated, the shuttle 984 moves the voice-coilactuator, and thus the actuator-aperture axis 911, orthogonal to adirection of the lens 920's motion caused by the voice-coil actuator,here along the y-axis. As such, when activated, the shuttle 984 isconfigured to displace the voice-coil actuator 930, and thus theactuator-aperture axis 911 and the lens 920, by a transversedisplacement δX_(C)≠0 relative to a transverse datum 989 (here aparticular surface of the rail 982).

The housing 912 has a scanning aperture 916, which is an opening in thehousing. The translation stage 980 supports the voice-coil actuator 930adjacent to the scanning aperture 916. In this manner, the lens 920coupled to the voice-coil actuator 930 (i) is oriented with its opticalaxis along the z-axis (here into the page), and (ii) is facing outsidethe housing 912 through the scanning aperture 916. The coupling frame917C supports the input optical port 914 adjacent to a side of the lens920 opposing the lens side facing the scanning aperture 916. The housing912 can have a source opening 918 configured like the source opening 318described above in connection with FIGS. 3A-3B. The fiber optic cable950 is connected at its input end to a laser source 902, crosses insidethe housing 912 (e.g., through the source opening 918), and is connectedat its output end to the input optic port 914 adjacent to the lens 920.In this manner, the fiber optic cable 950 provides at its output end,during operation of the scan head 910, laser light from the laser source902 in the form of a laser beam (not visible in FIG. 9) directed to thelens 920 along the actuator-aperture axis 911. The lens 920 isconfigured to (i) receive directly from the input optical port 914 theincident laser beam along the actuator-aperture axis 911 through theactuator aperture 934, and (ii) focus the transmitted laser beam (notvisible in FIG. 9) to a target surface 995.

Note that the fiber optic cable 950 has been provided with a loop 952 ofextra length to avoid stressing the fiber optic cable adjacent to thesource opening 918, and adjacent to the input optic port 914 (which canbe implemented as a fiber optic cable connector). The loop 952 can beinside the housing 912 or outside the housing 912 (e.g. the laser cancross inside the housing 912 through the optic port 914 being located inthe housing 912). Additionally, the loop 952 prevents stressing thefiber optic cable 950 during operation of the translation stage 980,when the shuttle 984 moves, along the x-axis, the input optic port 914,and thus the output end of the fiber optic cable.

Referring now to both FIGS. 8 and 9, the target surface 895, 995 (i) isspaced apart from the lens 820, 920 by a working distance along theactuator-aperture axis 811, 911, here into the page, and (ii) extendstransversely to the actuator-aperture axis, here parallel to the(x,y)-plane, within a field of view defined by the scanning aperture816, 916. While printing on the target surface 895, 995, the targetsurface 895, 995 can be moved along the x-axis (e.g., by a conveyor) toa specific x-coordinate, before bringing the target surface 895, 995 toa stop. The target surface 895, 995 will be stationary for a timeinterval, so motion of the actuator-aperture axis 811, 911 along thex-axis during this time interval will be caused by activating theshuttle 884, 984 to shift the actuator-aperture axis 811, 911 by adesired transverse displacement along the x-axis, as described below.

The voice-coil actuator 830, 930 includes two or more springs arrangedto compress and extend orthogonally to the actuator-aperture axis 811,911 here along the y-axis. As such, when the voice-coil actuator 830,930 has been activated, the springs are configured to linearly move thelens 820, 920 transversely to the actuator-aperture axis 811, 911. At atime “t”, the lens 820, 920 has been linearly moved along a linear pathperpendicular to the first actuator-aperture axis 811, 911, such that aninstance of its optical axis has shifted by a corresponding lensdisplacement δy(t)≠0 relative to the actuator-aperture axis. Asdescribed above in connection with FIGS. 2B-2C, 3A-3B, 4A-4B and 5A-5B,the finite lens displacement δy(t) causes that a corresponding instanceof the transmitted laser beam be redirected by the lens 820, 920 throughrefraction, relative to the actuator-aperture axis 811, 911 to a desiredlevel of the target surface 895, 995 separated along the y-axis from theactuator-aperture axis by a corresponding target displacement ΔY(t) (notvisible in FIGS. 8 and 9). Additionally, each of FIGS. 8 and 9 showsthat, at the same time, the translation stage 880, 980 has beenactivated using a transverse-range extension procedure to move thevoice-coil actuator 830, 930 and thus the actuator-aperture axis 811,911 and the lens, by a transverse displacement δX_(C)(t) correspondingto a desired lateral distance from the transverse datum 889, 989. Thishas shifted the actuator-aperture axis 811, 911 by δX_(C)(t). As aresult, the transmitted beam impinges on the target surface 895, 995 ata point separated (i) along the y-axis by a desired target displacementΔY(t) from the actuator-aperture axis 811, 911, and (ii) along thex-axis by a desired transverse displacement δX_(C)(t) from thetransverse datum 889, 989.

The translation stage 880, 980 of the scan head 810, 810 can shift theactuator-aperture axis 811, 911 along the x-axis over a maximumx-displacement δX_(CMAX). In some Implementations of the translationstage 880, 980, the maximum x-displacement can be between 50-200 mm.

In some implementations, the translation stage 880, 980 can be disposedexternally to the housing 812, 912 of the scan head 810, 910. Thiscorresponds to mounting the entire scan head 210, 310 on the shuttle884, 984 of the translation stage 880, 980. In the case of the scan head310 mounted on the shuttle 984 of the translation stage 980, the loop352 of the fiber optic cable 350 can wind and unwind to accommodate forthe input end of the fiber optic cable 650 coupled to the laser source302 “moving” near or away from the source opening 318. In the case ofthe scan head 210 mounted on the shuttle 884 of the translation stage880, a telescopic hollow tube with a constant inner diameter can bedisposed along the x-axis connected at an input end to the laser source202 and at an opposing output end the input optical port 214. In thismanner, the telescopic hollow tube can extend and collapse to shield thelaser beam 215 from the environment as the shuttle 984 moves the scanhead 210 between its nearest, to its farther, distance along the x-axisbetween the laser source 202 and the input optical port 214.

The scan heads 410, 510, 610, 710, 810 and 910 represent modificationsof the scan heads 210, 310 in which the voice-coil actuator 230, 330—towhich the lens 220, 320 has been coupled—was combined with one othervoice-coil actuator or translation stage. Other scan head embodimentsthat include combinations of the voice-coil actuator 230, 330—to whichthe lens 220, 320 has been coupled—with two or more from among thedisclosed voice-coil actuators and translation stages will be describedbelow in connection with FIG. 10.

FIG. 10 is a diagram of a laser marking system 1000 which includes alaser scanning device 1010, a laser source 1002, and a controller 1090.In this example, the laser marking system 1000 is used to produce apattern 1099 on a target surface 1095, the latter spaced apart by aworking distance W from the laser scanning device 1010 along the z-axis,and arranged parallel to the (x,y)-plane.

The laser source 1002 is configured and arranged to provide a laser beam1015. The laser scanning device 1010 includes an optical port 1014configured and arranged to receive the laser beam 1015 from the lasersource 1002. The laser scanning device 1010 also includes a lens 1020configured and arranged to focus the laser beam 1025 to modify thetarget surface 1095 of a material to be marked. Additionally, the laserscanning device 1010 includes an electrically controlled linear actuator1030 with an actuator aperture, which has an actuator-aperture axis 1011oriented along the z-axis. The lens 1020 is coupled to the electricallycontrolled linear actuator 1030 to cover the actuator aperture. Theelectrically controlled linear actuator 1030 is configured to move thelens 1020 linearly. In this manner, the electrically controlled linearactuator 1030 causes the laser beam 1025 to scan across the targetsurface 1095 as a result of changes in a refraction angle, of the laserbeam passing through the lens 1020, caused by the linear movement. Inthe example illustrated in FIG. 10, the electrically controlled linearactuator 1030 scans the laser beam 1025 transmitted through the lens1020 parallel to the (y,z)-plane.

In some implementations, the electrically controlled linear actuator1030 coupled with the lens 1020 can be configured similar to thevoice-coil actuator 130. In some implementations, the electricallycontrolled linear actuator 1030 coupled with the lens 1020 can beconfigured similar to the voice-coil actuator 130R. Optionally, theelectrically controlled linear actuator 1030 can be rotated about theactuator-aperture axis 1011, such that it scans the laser beam 1025transmitted through the lens 1020 parallel to the (x,z)-plane.

In some embodiments described in detail below, the laser scanning device1010 can include one, two or all of an electrically controlled autofocusactuator 1060, an electrically controlled scanning-range extenderactuator 1070 or an electrically controlled sideways-mover actuator1080, two or more of which can be coupled together by a chassis 1017 ofthe scanning device 1010.

The controller 1090 is coupled through a communication interface 1094with, and is configured to control, the laser scanning device 1010. Insome implementations, the controller 1090 is coupled through thecommunication interface 1094 with both the laser source 1002 and thelaser scanning device 1010, and is configured to control both of them.The controller 1090 includes a hardware processor 1092 and memory 1096coupled with the hardware processor. In some implementations, at leastsome of the components of the controller are internal to the laserscanning device 1010. The memory is configured to store scanninginstructions 1098 that, when performed by the hardware processor 1092,cause the controller 1090 to send electrical signals to the electricallycontrolled linear actuator 1030 to move the lens 1020 to effect dotmatrix or vector type laser marking on products, e.g., like the targetsurface 1095. Here, the target surface 1095 suitably moves, e.g., alongthe x-axis, in front of the laser scan head 1010 on a conveyor 1091 in aproduct manufacturing or packaging facility, for instance. The laserbeam 1025 transmitted through the lens 1020 is used to print, markand/or burn a pattern 1099 on the surface 1095 of the material to bemarked (e.g., by ablation or using phase changing inks). Theinstructions 1098 can further cause the controller 1090 to sendelectrical signals to (i) the electrically controlled autofocus actuator1060 to move the lens 1020 axially to effect focusing of the lens ontothe target surface 1095, and (ii) the electrically controlledscanning-range extender actuator 1070 and/or the electrically controlledsideways-mover actuator 1080 to shift the actuator-aperture axis 1011 toincrease the printing range over the target surface 1095.

In some implementations, the laser scanning device 1010 can beimplemented as the scan head 210. Here, the laser scanning device 1010includes discrete relay optics, e.g., 242, 244 (not shown in FIG. 10),arranged and configured to redirect the laser beam 1015 received throughthe optical port 1014, and provide the redirected laser beam to the lens1020 along the actuator-aperture axis 1011. In other implementations,the laser scanning device 1010 can be implemented as the scan head 310.Here, the laser marking system 1000 includes a fiber optics cable, e.g.,350 (not shown in FIG. 10), and the optical port 1014 is configured as afiber optic cable connector disposed adjacent to the lens 1020. Thefiber optics cable is coupled at its input end to the laser source 1002and at its output end to the fiber optic cable connector of the laserscanning device 1010 to guide laser light from the laser source to thelaser scanning device. In this manner, the laser light output throughthe fiber optic cable connector is provided as the laser beam 1015 alongthe actuator-aperture axis 1011 directly to the lens 1020.

In a first embodiment, the laser scanning device 1010 suitably includes,in addition to the lens 1020 and the electrically controlled linearactuator 1030 coupled with the lens to scan the transmitted laser beam1025 in a scanning plane, here parallel to the (y,z)-plane, theelectrically controlled autofocus actuator 1060 coupled with theelectrically controlled linear actuator 1030. The electricallycontrolled autofocus actuator 1060 (e.g., implemented as the voice-coilactuator 460, 560) will controllably move the electrically controlledlinear actuator 1030, and thus the lens 1020, along theactuator-aperture axis 1011 to ensure that the laser beam 1025 thatimpinges on the target surface 1095 is in focus. For example, the firstembodiment of the laser scanning device 1010 can be implemented as thescan head 410 described in detail in connection with FIGS. 4A-4B. Asanother example, the first embodiment of the laser scanning device 1010can be implemented as the scan head 510 described in detail inconnection with FIGS. 5A-5B.

In a second embodiment, the laser scanning device 1010 suitablyincludes, in addition to the lens 1020 and the electrically controlledlinear actuator 1030 coupled with the lens to scan the transmitted laserbeam 1025 in the scanning plane, the electrically controlledscanning-range extender actuator 1070 coupled with the electricallycontrolled linear actuator 1030. The electrically controlledscanning-range extender actuator 1070 (e.g., implemented as thevoice-coil actuator 670, 770) will shift the electrically controlledlinear actuator 1030 and its actuator-aperture axis 1011 transverselywithin the scanning plane to ensure that the actuator-aperture axis 1011intersects the target surface 1095 at a desired elevation coordinate,along the y-axis relative to a datum 1019 (e.g., a point of a chassis ofthe laser scanning device 1010). For example, the second embodiment ofthe laser scanning device 1010 can be implemented as the scan head 610described in detail in connection with FIGS. 6A-6B. As another example,the second embodiment of the laser scanning device 1010 can beimplemented as the scan head 710 described in detail in connection withFIGS. 7A-7B.

In a third embodiment, the laser scanning device 1010 suitably includes,in addition to the lens 1020 and the electrically controlled linearactuator 1030 coupled with the lens to scan the transmitted laser beam1025 in the scanning plane, the electrically controlled sideways-moveractuator 1080 coupled with the electrically controlled linear actuator1030. The third embodiment of the laser scanning device 1010 can be usedwhen the conveyor 1091 is at rest or moving relating to the laserscanning device. The electrically controlled sideways-mover actuator1080 (e.g., implemented as the translation stage 880, 980) will shiftthe electrically controlled linear actuator 1030 and itsactuator-aperture axis 1011 transversely within the (x,z)-plane, normalto the scanning plane, to ensure that the actuator-aperture axis 1011intersects the target surface 1095 at a desired lateral coordinate,along the x-axis relative to a datum 1019. For example, the thirdembodiment of the laser scanning device 1010 can be implemented as thescan head 810 described in detail in connection with FIG. 8. As anotherexample, the third embodiment of the laser scanning device 1010 can beimplemented as the scan head 910 described in detail in connection withFIG. 9.

In a fourth embodiment, the laser scanning device 1010 suitablyincludes, in addition to the lens 1020 and the electrically controlledlinear actuator 1030 coupled with the lens to scan the transmitted laserbeam 1025 in the scanning plane, the electrically controlled autofocusactuator 1060 coupled with the electrically controlled linear actuator1030, and the electrically controlled scanning-range extender actuator1070 coupled with the electrically controlled autofocus actuator 1060.Here, the electrically controlled scanning-range extender actuator 1070(e.g., implemented as the voice-coil actuator 670, 770) will shift theelectrically controlled autofocus actuator 1060, and thus theelectrically controlled linear actuator 1030 and its actuator-apertureaxis 1011, transversely within the scanning plane to ensure that theactuator-aperture axis 1011 intersects the target surface 1095 at adesired elevation coordinate, along the y-axis relative to a datum 1019.Additionally, the electrically controlled autofocus actuator 1060 (e.g.,implemented as the voice-coil actuator 460, 560) will controllably movethe electrically controlled linear actuator 1030, and thus the lens1020, along the y-shifted actuator-aperture axis 1011 to ensure that thelaser beam 1025 that impinges on the target surface 1095 at the desiredelevation coordinate is in focus.

In a fifth embodiment, the laser scanning device 1010 suitably includes,in addition to the lens 1020 and the electrically controlled linearactuator 1030 coupled with the lens to scan the transmitted laser beam1025 in the scanning plane, the electrically controlled autofocusactuator 1060 coupled with the electrically controlled linear actuator1030, and the electrically controlled sideways-mover actuator 1080coupled with the electrically controlled autofocus actuator 1060. Thefifth embodiment of the laser scanning device 1010 can be used when theconveyor 1091 is at rest or moving relating to the laser scanningdevice. Here, the electrically controlled sideways-mover actuator 1080(e.g., implemented as the translation stage 880, 980) will shift theelectrically controlled autofocus actuator 1060, and thus theelectrically controlled linear actuator 1030 and its actuator-apertureaxis 1011, transversely within the (x,z)-plane, normal to the scanningplane, to ensure that the actuator-aperture axis 1011 intersects thetarget surface 1095 at a desired lateral coordinate, along the x-axisrelative to a datum 1019. Additionally, the electrically controlledautofocus actuator 1060 (e.g., implemented as the voice-coil actuator460, 560) will controllably move the electrically controlled linearactuator 1030, and thus the lens 1020, along the x-shiftedactuator-aperture axis 1011 to ensure that the laser beam 1025 thatimpinges on the target surface 1095 at the desired lateral coordinate isin focus.

In a sixth embodiment, the laser scanning device 1010 suitably includes,in addition to the lens 1020 and the electrically controlled linearactuator 1030 coupled with the lens to scan the transmitted laser beam1025 in the scanning plane, the electrically controlled scanning-rangeextender actuator 1070 coupled with the electrically controlled linearactuator 1030, and the electrically controlled sideways-mover actuator1080 coupled with the electrically controlled scanning-range extenderactuator 1070. The sixth embodiment of the laser scanning device 1010can be used when the conveyor 1091 is at rest or moving relating to thelaser scanning device. Here, the electrically controlled sideways-moveractuator 1080 (e.g., implemented as the translation stage 880, 980) willshift the electrically controlled scanning-range extender actuator 1070,and thus the electrically controlled linear actuator 1030 and itsactuator-aperture axis 1011, transversely within the (x,z)-plane, normalto the scanning plane, to ensure that the actuator-aperture axis 1011intersects the target surface 1095 at a desired lateral coordinate,along the x-axis relative to a datum 1019. Additionally, theelectrically controlled scanning-range extender actuator 1070 (e.g.,implemented as the voice-coil actuator 670, 770) will shift theelectrically controlled linear actuator 1030 and its x-shiftedactuator-aperture axis 1011 transversely within the x-shifted scanningplane to ensure that the x- and y-shifted actuator-aperture axis 1011intersects the target surface 1095 at a desired elevation coordinate,along the y-axis relative to the datum 1019, at the desired lateralcoordinate.

In a seventh embodiment, the laser scanning device 1010 suitablyincludes, in addition to the lens 1020 and the electrically controlledlinear actuator 1030 coupled with the lens to scan the transmitted laserbeam 1025 in the scanning plane, the electrically controlled autofocusactuator 1060 coupled with the electrically controlled linear actuator1030, the electrically controlled scanning-range extender actuator 1070coupled with the electrically controlled autofocus actuator 1060, andthe electrically controlled sideways-mover actuator 1080 coupled withthe electrically controlled scanning-range extender actuator 1070. Theseventh embodiment of the laser scanning device 1010 can be used whenthe conveyor 1091 is at rest or moving relating to the laser scanningdevice. Here, the electrically controlled sideways-mover actuator 1080(e.g., implemented as the translation stage 880, 980) will shift theelectrically controlled scanning-range extender actuator 1070, and thusthe electrically controlled autofocus actuator 1060 and the electricallycontrolled linear actuator 1030 and its actuator-aperture axis 1011,transversely within the (x,z)-plane, normal to the scanning plane, toensure that the actuator-aperture axis 1011 intersects the targetsurface 1095 at a desired lateral coordinate, along the x-axis relativeto a datum 1019. Further, the electrically controlled scanning-rangeextender actuator 1070 (e.g., implemented as the voice-coil actuator670, 770) will shift the electrically controlled autofocus actuator 1060and thus the electrically controlled linear actuator 1030 and itsx-shifted actuator-aperture axis 1011 transversely within the x-shiftedscanning plane to ensure that the x- and y-shifted actuator-apertureaxis 1011 intersects the target surface 1095 at a desired elevationcoordinate, along the y-axis relative to the datum 1019, at the desiredlateral coordinate. Furthermore, the electrically controlled autofocusactuator 1060 (e.g., implemented as the voice-coil actuator 460, 560)will controllably move the electrically controlled linear actuator 1030,and thus the lens 1020, along the x- and y-shifted actuator-apertureaxis 1011 to ensure that the laser beam 1025 that impinges on the targetsurface 1095 at the desired lateral coordinate and elevation coordinateis in focus.

A few embodiments have been described in detail above, and variousmodifications are possible. While this specification contains manyspecifics, these should not be construed as limitations on the scope ofwhat may be claimed, but rather as descriptions of features that may bespecific to particular embodiments. Certain features that are describedin this specification in the context of separate embodiments can also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment canalso be implemented in multiple embodiments separately or in anysuitable subcombination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the embodiments described above should not be understoodas requiring such separation in all embodiments.

The controller 1090 can be one controller, as shown, or the controller1090 can be more than one controller 1090. The controller(s) 1090 can beintegrated with respective components of the system 1000, asappropriate. In various implementations, one or more controllers 1090can be implemented using one or more programmable hardware processorsexecuting one or more computer programs (e.g., operating system codeembedded in firmware and/or application code stored in a non-transitorycomputer-readable medium), special purpose logic circuitry (e.g., usingFPGA (field programmable gate array) or ASIC (application specificintegrated circuit) circuitry), or a combination thereof.

Hardware processors suitable for the execution of a computer programinclude, by way of example, both general and special purposemicroprocessors, and any one or more processors of any kind of digitalcomputer. Generally, a processor will receive instructions and data froma read only memory or a random access memory or both. The essentialelements of a computer are a processor for performing instructions andone or more memory devices for storing instructions and data. Generally,a computer will also include, or be operatively coupled to receive datafrom or transfer data to, or both, one or more mass storage devices forstoring data, e.g., magnetic, magneto optical disks, or optical disks.However, a computer need not have such devices. Moreover, a computer canbe embedded in another device, such as a mobile telephone, a personaldigital assistant (PDA), a mobile audio or video player, a controllerfor a laser printer/marking device, to name just a few. Devices suitablefor storing computer program instructions and data include all forms ofnon-volatile memory, media and memory devices, including by way ofexample semiconductor memory devices, e.g., EPROM (Erasable ProgrammableRead-Only Memory), EEPROM (Electrically Erasable Programmable Read-OnlyMemory), and flash memory devices; magnetic disks, e.g., internal harddisks or removable disks; magneto optical disks; and CD ROM and DVD-ROMdisks. The processor and the memory can be supplemented by, orincorporated in, special purpose logic circuitry.

To provide for interaction with a user, embodiments of the subjectmatter described in this specification can be implemented on a computerhaving a display device, e.g., an LCD (liquid crystal display) displaydevice, an OLED (organic light emitting diode) display device, oranother monitor, for displaying information to the user, and a keyboardand a pointing device, e.g., a mouse or a trackball, by which the usercan provide input to the computer. Other kinds of devices can be used toprovide for interaction with a user as well; for example, feedbackprovided to the user can be any form of sensory feedback, e.g., visualfeedback, auditory feedback, or tactile feedback; and input from theuser can be received in any form, including acoustic, speech, or tactileinput.

Other embodiments fall within the scope of the following claims.

What is claimed is:
 1. A laser scanning device for marking objects, thelaser scanning device comprising: an optical port configured andarranged to receive a laser beam; a lens configured and arranged tofocus the laser beam to modify a surface of a material to be marked; andan electrically controlled linear actuator coupled with the lens, theelectrically controlled linear actuator being configured to move thelens linearly, thereby causing the laser beam to scan across the surfaceof the material to be marked as a result of changes in a refractionangle, of the laser beam passing through the lens, caused by the linearmovement.
 2. The laser scanning device of claim 1, comprising: a firstreflector optically coupled with the optical port; and a secondreflector optically coupled with the first reflector and the lens,wherein the first reflector is arranged to receive the laser beam fromthe optical port along a first direction, and configured to redirect thelaser beam to the second reflector along a second direction, and whereinthe second reflector is arranged to receive the laser beam along thesecond direction, and redirect the laser beam to the lens along a thirddirection.
 3. The laser scanning device of claim 2, wherein the firstreflector comprises a first mirror, and the second reflector comprises asecond mirror.
 4. The laser scanning device of claim 2, comprising: atranslation stage that supports the first reflector and the secondreflector, in addition to the electrically controlled linear actuatorand thus the lens, wherein the translation stage is configured to move,as a unit, each of the first mirror, the second mirror, the electricallycontrolled linear actuator, and the lens, along a line that is parallelto the first direction.
 5. The laser scanning device of claim 4 or 10,wherein the translation stage comprises a table, a thread shaft, and astepper motor.
 6. The laser scanning device of claim 2, wherein thesecond direction is along an X dimension in a three dimensional space,the first reflector is arranged in a plane tilted at a fixed forty fivedegree angle relative to a (X,Z)-plane and normal to a (X,Y)-plane inthe three dimensional space, the third direction is along a Y dimensionin the three dimensional space, the second mirror is arranged in a planetilted at a fixed forty five degree angle relative to the (X,Z)-planeand normal to a (Y,Z)-plane in the three dimensional space, and thefirst direction is along a Z dimension in the three dimensional space.7. The laser scanning device of claim 2 or 4, wherein the electricallycontrolled linear actuator is a first electrically controlled linearactuator configured to move the lens along the second direction, and thelaser scanning device further comprises a second electrically controlledlinear actuator coupled with the first electrically controlled linearactuator, the second electrically controlled linear actuator beingconfigured to move the first electrically controlled linear actuator,and thus the lens, along the third direction to adjust the focus of thelaser beam on the surface of the material to be marked.
 8. The laserscanning device of claim 2 or 4 or 7, further comprising a thirdelectrically controlled linear actuator coupled with the firstelectrically controlled linear actuator, the third electricallycontrolled linear actuator being configured to move, as a unit, thesecond mirror and the first electrically controlled linear actuator, andthus the lens, along the second direction to adjust a centered positionof the lens, thereby providing an increased marking area for the laserscanning device.
 9. The laser scanning device of claim 1, wherein theoptical port comprises a fiber optic cable connector configured to holdan output end of a fiber optic cable, the fiber optic cable connectordisposed adjacent to the lens and arranged to direct to the lens along athird direction the laser beam guided through the fiber optic cable andoutput at its output end.
 10. The laser scanning device of claim 9,comprising: a translation stage that supports the fiber optic cableconnector, and the electrically controlled linear actuator and thus thelens; wherein the translation stage is configured to move, as a unit,each of the fiber optic cable connector, the electrically controlledlinear actuator, and the lens, along a line that is parallel to a firstdirection orthogonal to the third direction.
 11. The laser scanningdevice of claim 9 or 10, wherein the electrically controlled linearactuator is a first electrically controlled linear actuator configuredto move the lens along a second dimension orthogonal to the first andthird directions, and wherein the laser scanning device comprises asecond electrically controlled linear actuator coupled with the firstelectrically controlled linear actuator, the second electricallycontrolled linear actuator being configured to move, as a unit, thefiber optic cable connector, the first electrically controlled linearactuator, and thus the lens, farther along the second dimension toadjust a centered position of the lens, thereby providing an increasedmarking area for the laser scanning device.
 12. The laser scanningdevice of claim 9 or 10 or 11, further comprising a third electricallycontrolled linear actuator coupled between the first electricallycontrolled linear actuator and the second electrically controlled linearactuator, the third electrically controlled linear actuator beingconfigured to move the first electrically controlled linear actuator,and thus the lens, along the third direction to adjust the focus of thelaser beam on the surface of the material to be marked.
 13. The laserscanning device of any of claims 1-12, wherein a ratio of a diameter ofthe lens divided by a diameter of the laser beam is between 1.1 and 5.1,between 1.1 and 4.1, between 1.1 and 3.1, or between 1.1 and 2.1. 14.The laser scanning device of claim 13, wherein the diameter of the laserbeam is about 2.5 mm, the diameter of the lens is about 3.5 mm, and ascanning distance covered by the changes in the refraction angle between15 mm and 57 mm.
 15. The laser scanning device of any one of thepreceding claims, wherein any of the electrically controlled linearactuators referenced therein comprises either a voice-coil actuator or alinear DC motor.
 16. The laser scanning device of any one of thepreceding claims, wherein the linear motion of the lens caused by theelectrically controlled actuator coupled with the lens is along a linearpath or an arcuate path.
 17. A laser marking system comprising: a laserscan head comprising the laser scanning device of any one of claims 1-8;and a laser source configured and arranged to provide the laser beam tothe optical port of the laser scan head along the first direction.
 18. Alaser marking system comprising: a laser scan head comprising the laserscanning device of any one of claims 9-12; a laser source configured andarranged to provide the laser beam; and the fiber optic cable connectedat its input end to the laser source and at its output end to the fiberoptic cable connector of the laser scan head to guide the laser beamfrom the laser source to the laser scan head.
 19. The laser makingsystem of claim 17 or 18, comprising: a controller coupled with thelaser scan head and configured to send electrical signals to theelectrically controlled linear actuator to move the lens to effect dotmatrix or vector type laser marking on products, when the products movein front of the laser scan head on a conveyor in a product manufacturingor packaging facility.
 20. A method of operating the laser system ofclaim 19, substantially as shown and described.